1. Field of the Invention
The present invention relates to a toner cartridge and an image forming apparatus for mounting the toner cartridge.
2. Description of the Related Art
Copier manufacturers, from the view point of product control and security of print quality, list several toner cartridges recommended to use for their manufactured copiers. The reason is that use of a toner cartridge of poor quality may cause copier breakdowns and deterioration of the print quality.
However, a toner cartridge mounted in a copier, regardless of the type of copier, has a similar shape and size. Therefore, it is difficult for a user to discriminate correctly the kind of toner cartridge and depending on the condition, a wrong toner cartridge may be mounted. Therefore, in recent years, several copiers capable of preventing use of a toner cartridge which is not a true product without depending on the judgment of the user have been developed.
For example, a copier for preventing mounting itself of a toner cartridge which is not a true product by use of the fitting condition of the concavity and convexity formed in the cap of the toner cartridge and the concavity and convexity formed in the coupling of the cartridge driver is known.
In this copier, when mounting and demounting the toner cartridge, a cartridge holder is used. The cartridge holder is rotatably supported by the connection section arranged in the copier body and moves the held toner cartridge back and forth between the mounting position in the copier body and the release position outside the copier body.
The cartridge driver is provided in the neighborhood of the connection section for supporting the cartridge holder and in the coupling thereof, the cap of the toner cartridge is inserted.
Further, in the copier body, when the toner cartridge is mounted in the copier body, in the position opposite to the cartridge driver, a pusher for pressing the toner cartridge toward the cartridge driver is provided.
When mounting the toner cartridge, if the concavity and convexity provided in the cap and the concavity and convexity provided in the coupling do not correspond to each other, the end of the toner cartridge is projected from the cartridge holder, thus the toner cartridge and pusher interfere with each other. By doing this, the toner cartridge is obstructed by the pusher and is not mounted smoothly in the copier body.
However, if the concavity and convexity provided in the cap and the concavity and convexity provided in the coupling correspond to each other, the end of the toner cartridge is not projected from the cartridge holder, thus the toner cartridge and pusher do not interfere with each other. Therefore, the toner cartridge is not obstructed by the pusher and is mounted smoothly in the copier body.
As mentioned above, in this copier, the toner cartridge which is not a true product is not mounted in the copier body, so that the toner cartridge which is not a true product will not be used.
Further, in Japanese Patent Application 2001-125354, a copier for preventing use of a toner cartridge which is not a true product by use of the switch driver provided in the toner cartridge and the switch provided in the developing device is disclosed.
In this copier, only when the switch of the developing device is turned on by the switch driver of the toner cartridge, toner supply to the developing device is started. Therefore, if the toner cartridge is provided with the switch driver, simultaneously with mounting of the toner cartridge in the copier, the switch of the developing device is turned on and toner supply to the developing device is started.
However, if the toner cartridge has no switch driver, even if the toner cartridge is correctly mounted in the copier body, the switch of the developing device is not turned on, so that toner supply to the developing device is not started.
As mentioned above, in this copier, if the toner cartridge has no switch driver, when the developing device is not turned on, even if a toner cartridge which is not a true product is mounted, the toner cartridge is not used actually.
As mentioned above, in the copier having the cartridge holder, if the toner cartridge is projected from the cartridge holder, when the toner cartridge is mounted, the toner cartridge and pusher interfere with each other, thus the toner cartridge cannot be mounted.
However, when the pusher is deformed, even if the toner cartridge is projected from the cartridge holder, the toner cartridge may be mounted. Further, even when the pusher is not deformed, depending on the shape and dimensions of the toner cartridge, large force can be applied, thus the toner cartridge may be mounted. As mentioned above, the copier using the fitting condition of the concavities and convexities cannot prevent surely use of a toner cartridge which is not a true product.
Further, the copier disclosed in Japanese Patent Application 2001-125354 requires the switch driver and switch, so that the constitution of the copier is complicated and furthermore, the cost is increased.
The toner cartridge used in the image forming apparatus aforementioned is of a rotary type as disclosed in Japanese Patent Application 2004-280064. Generally, the rotary-type toner cartridge is in a cylinder shape and so that a user himself can exchange the cartridge, is removably mounted in the image forming apparatus. Therefore, the toner cartridge is desirably shaped so that the user can remove simply and quickly the toner cartridge from the image forming apparatus.
The toner cartridge disclosed in Japanese Patent Application 2004-280064 includes a toner bottle for storing toner, a toner cap for blocking the opening of the toner bottle, and a gear for driving the toner bottle to rotate.
The toner bottle includes a cylindrical portion uniform in thickness arranged on the opposite side of the bottle cap and a contracting diameter portion which is arranged halfway between the bottle cap and the cylindrical portion and whose inside diameter contracts in the separating direction from the cylindrical portion.
On the other hand, the outside diameter of the contracting diameter portion disclosed in Japanese Patent Application 2004-280064, similarly to the inside diameter, contracts slightly as it approaches the toner cap. However, on the outer peripheral surface of the contracting diameter portion, the gear for driving the toner bottle to rotate is arranged, so that the outside diameter of the entire toner cartridge is almost uniform. Moreover, the toner bottle has an outside diameter formed large so as to store much toner. Namely, in the toner cartridge disclosed in Japanese Patent Application 2004-280064, the outside diameter is too large for a user and the part for putting a finger on is provided little. Therefore, the removal operation for the toner cartridge is difficult.
Further, on the inner peripheral surface of the contracting diameter portion of the toner cartridge disclosed in Japanese Patent Application 2004-280064, no spiral projection portion for conveying toner is formed. Therefore, even if the toner cartridge rotates, toner stored in the toner bottle is not conveyed smoothly to the vent.